Breivik's lawyer Øystein Storrvik told Norway’s VG newspaper that he delivered a subpoena to the Oslo District Court on Wednesday.
“The main reason for the lawsuit is the extreme isolation my client has been subjected to,” he told the newspaper.
Storrvik has been Breivik's lawyer since February this year, when he and his longstanding defence lawyer Geir Lippestad stopped working together over Lippestad's unwillingness to take the government to court on Breivik's terms.
“We have looked at the possibility of bringing a court case about prison conditions, but we disagree on what is reasonable,” Lippestad told VG at the time. “There is a discrepancy between Breivik's wishes and what is appropriate for us to offer him.”
In the current court case, Breivik argues that his complete isolation from other prisoners violates the European Convention on Human Rights.
Breivik is the only Norwegian prisoner to be held in his own wing without any contact with other inmates.
Earlier this month he was threatened in prison by another inmate, despite living under the highest security of any prisoner in Norway.
The rogue inmate, who managed to enter Breivik’s personal section of Skien prison from the prison yard in April, hammered at the door of Breivik’s cell while shouting death threats.
“If there wasn’t a door between us, I’d kill you,” the intruder said, according to a letter Breivik sent to Norway’s Press Complaints Commission.
“That was a quite special case,” Storrvik said according to Reuters. “I really mean that it should be possible for him to have contact with other people without getting hurt.”
He now demands that his prison conditions are changed, so that he can interact with others, and send and receive post without censorship.
“In principle, he has had no contact with anyone other than prison officers and health care providers during the four years he has served, aside from than five minutes to hug his mother before she died,” Storrvik said.
The Norwegian government has previously ruled that Breivik’s prison conditions comply with European law.
Breivik was sentenced in 2012 to 21 years in prison for his brutal twin terror attacks on 22 July 2011, which cost 77 people their lives.